The storm of outrage that the Rethuglicans and their friends in the Beltway media are stoking over the IRS' scrutiny of conservative 501(c) (4) groups that were applying for tax exempt status might note this.
At least three progressive groups were also scrutinized over whether they were a "social welfare" group, as required by the above-mentioned IRS code.
If you consider that the outpouring of right-wing corporate money into conservative 501(c) (4) groups has overwhelmed similar progressive groups since Citizens United came along, you'll understand why the vast majority of groups examined were right-wing and not progressive. So when you hear some boob on, say, Morning Joke, wax indignant over the IRS' blundering, remember that it was the Rethug-backed Citizens United case that opened the door to gaming the tax code to fund sleazy political ads, and the IRS has been walking a tightrope ever since.